Elevator starting

ABSTRACT

Utilizing an auxiliary power supply to start the motor-generator set of an elevator system in which the set has a primary motor with a large starting current requirement which may not be met by the auxiliary supply and in which the rotor of the motor is mechanically coupled to the rotor of a secondary motor whose starting current requirement is satisfied by the output of the auxiliary supply by energizing the secondary motor from the auxiliary supply until the rotational speed of the coupled rotors reaches a predetermined value at which the current demand of the primary motor is within the output capability of the auxiliary supply and then electrically connecting the auxiliary supply to drive the primary motor.

United States Patent Abbott 1 Apr. 25, 1972 4] ELEVATOR STARTING Primary Examiner-Bernard A. Gilheany Assistant Examiner-W. E. Duncanson, Jr. [72] Inventor. giztgggluglgdsagshlgttgjm Webster Street, Atmmey w R- Hulben ['22] Filed: Aug. 27, 1969 [57] ABSTRACT Utilizing an auxiliary power supply to start the motor-generator set of an elevator system in which the set has a primary motor with a large starting current requirement which may not ..l87/29 be met by the auxiliary supply and in which the rotor of the i 136 137 motor is mechanically coupled to the rotor of a secondary 318/440 motor whose starting current requirement is satisfied by the output of the auxiliary supply by energizing the secondary motor from the auxiliary supply until the rotational speed of [56] References cued the coupled rotors reaches a predetermined value at which the UNITED STATES PATENTS current demand of the primary motor is within the output capability of the auxiliary supply and then electrically con g necting the auxiliary supply to drive the primary motor. outon et a 8 Claims, 3 Drawing Figures NORMAL POWER SUPPLY i l 24 ELEVATOR MOTOR EXCITER MOTOR l7 I ARMATURE ARMAruRE ARMATURE 19 GENERATOR 1 HELD 26 lZH SWITCHING F 28 SA ETY CIRCUIT SWITCHES DOOR MOTOR 34 32 EMERGENCY BRAKE POWER CONTROLLER H COIL S U P P LY PATENTEBAPR 2 s 1912 SHEET 1 UF 2 NORMAL POWER FIG I SUPPLY #14 I L ELEVATOR MOTOR '7 EXCITER MOTOR ROTOR a ARMATuRE ARMATuRE ARMATURE I9 22 GENERATOR 2O FIELD SWITCHING 28 SWITCHES DOOR MOTOR .L H........-]L. ..L Z 32 EMERGENCY BRAKE POWER CONTROLLER CO'L SUPPLY ELEVATOR STARTING This invention relates to auxiliary elevator operation.

It is a principal object of the present invention to provide a method and apparatus for operating an elevator, upon deenergization of the normal power supply, with an auxiliary power supply that is far smaller than those heretofore required. Other objects include providing an auxiliary operation system that is easily installed and incorporated into existing elevator systems and that is inexpensive, compact, reliable, and quickly and efficiently operated.

The invention features utilizing an auxiliary power supply to start the motor-generator set of an elevator system in which the set has a primary motor with a large starting current requirement which may not be met by the auxiliary supply and in which the rotor of the primary motor is mechanically coupled to the rotor of a secondary motor whose starting current requirement is satisfied by the output of the auxiliary supply by energizing the secondary motor from the auxiliary supply until the rotational speed of the coupled rotors reaches a predetermined value at which the current demand of the primary motor is within the output capability of the auxiliary supply and then electrically connecting the auxiliary supply to drive the primary motor. In preferred embodiments in which the secondary motor is a D.C. exciter, there is featured applying power to the exciter field through one circuit, applying power to the exciter armature through a second circuit, increasing the voltage applied to the armature when the speed of rotation thereof reaches a predetermined speed, and disconnecting the exciter field and circuit from the auxiliary supply when applying power from the auxiliary supply to the motor of the set.

Other objects, features and advantages will become apparent from the following description of a preferred embodiment of the invention, taken together with the attached drawings thereof, in which:

FIG. 1 is a block diagram of an elevator power and control system according to the present invention; and

FIGS. 2 and 3 are schematic wiring diagrams of portions of the system of FIG. 1.

Referring to FIG. 1, the elevator installation, in normal operation, is powered by a 480 volt A.C. normal power supply connected to the elevator motor-generator set motor 16 by a switch 14 (for example a normally closed contact pair on the circuit breaker for the normal power supply) which is arranged to open when normal supply 10 is interrupted. Motorgenerator set 16 includes a standard 50 horsepower squirrel cage induction motor. The armature of exciter 18 is (as indicated by schematic connection 19) fixed to the same shaft as the generator armature and the motor driving rotor 17 of motor-generator set 16, so that the exciter armature 20, the motor-generator armature and rotor 17 always rotate together. Motor-generator set 16, when energized, is arranged to energize armature 22 of elevator main motor 24 directly. Exciter 18 is arranged to energize, through standard safety switches 32, field 26 of motor 24, door motor 28, and brake coil 30, when controls in controller 33 and corresponding respectively, to main motor 24, door motor 28 and brake coil 30 are operated and the appropriate switches 32 are closed. Safety switches 32 are provided to insure safe elevator operation. For example, one of switches 32 is arranged to open and to prevent coil 30 from becoming energized and lifting the elevator brake if motor 24 is de-energized.

An emergency system including a 208 volt A.C. emergency power supply 34 arranged to energize a switching circuit 36 is provided for operating the elevator when normal supply 10 fails. As described more fully hereinafter, circuit 36, when energized initially, is arranged to open one of safety switches to prevent operation of the elevator and apply power to exciter mechanically to rotate the rotor and armature 17 of motor-generator set 16. When the rotor and armature 17 are rotating (driven by armature 20 of exciter 18) at approximately their normal full-load speed, circuit 36 is arranged to close the safety switches and apply power to the motor-generator set.

Referring now to FIG. 2, there is illustrated two circuits, each fused for 60 amps, connected in parallel between the bus 50 of a D.C. supply voltage (approximately 130 volts) and ground 52. The first circuit includes exciter armature 20 (comprising armature windings 54 and 0.75 ohm armature resistance 56) and, connected in parallel therewith, the exciter shunt field 61 (comprising shunt field windings 60 and 40 ohm shunt field resistance 62).

The second circuit includes 0.001 ohm exciter series field resistance 58 and, connected in series with resistance 58 and in parallel with each other, motor field 26 (comprising windings 46 and 10 ohm field resistance 48) and safety subcircuit 59. Safety subcircuit includes a potential relay 64 (which is a portion of controller 33) and, connected in parallel therewith, normally open contact pair 64-1 and other circuits 66 (such as safety switches 32, brake coil 30 and door motor 28).

The circuits of FIG. 2 are provided with six terminals for connection to the switching circuit 36 of the emergency system. Terminals 66 and 68 are provided in the shunt field circuit of exciter l8, terminals 72 and 74 are provided in the branch of safety subcircuit 59 in series with relay 64, terminal 76 is connected to bus 50 and terminal 78 is provided, as shown, in the armature and shunt field circuit of exciter 18.

FIG. 3 illustrates, schematically, circuit 36 connected to emergency supply 34 and to terminals 66 through 78 of the circuits of FIG. 2. As shown, circuit 36 includes a transformerrectifier set 82 which provides a 135 volt D.C. supply voltage and powers, from terminal 86, a control subcircuit 84, an exciter armature power subcircuit 88, and an exciter field power subcircuit 85. Armature power subcircuit 88 is fused at and rated for 60 amps. Subcircuits 84 and 85 are together fused at and rated for 10 amps. Circuit 36 also includes a safety subcircuit 87.

Control subcircuit 84 has three relays, designated 38, 40, and 42, and armature power subcircuit 88 has one relay, designated 94. Relay 38 has normally closed contact pair 38-1 in safety subcircuit 87 and normally open contact pairs 38-2 and 383 in, respectively, subcircuits 84 and 88. Relay 40 has nonnally open contact pairs 40-l (in subcircuit 85) and 40-2 (in subcircuit 88) and normally closed contact pair 40-3 (in subcircuit 84). Relay 42 has normally open contact pairs 42-] (in subcircuit 87) and 42-2 (connected between supply 34 and motor-generator set 16) and normally closed contact pairs 42- 3 (in subcircuit 84) and 42-4 (in subcircuit 85 Relay 94 has normally open contact pair 94-1 and normally closed contact pair 94-4 (both in subcircuit 84) and normally open contact pairs 94-2 (in subcircuit 88) and 94-3 (in subcircuit 85).

Relay 38 is connected between the 135 volt D.C. supply and ground 96 in series with normally open contact pair 98 (which is on the main circuit breaker for normal supply 10 and closes when the normal power supply fails) and a normally open keyoperated switch 100, and is arranged to be energized when contact pair 98 and switch 100 are closed. Relay 40 is connected between the D.C. supply and ground 96 through contact pairs 38-2, 42-3, and 94-4, is shunted by microfarad capacitor 102, and is arranged to be energized when all of pairs 38-2, 42-3, and 94-4 are closed. Capacitor 102 is arranged to become charged when relay 40 is energized, and after the D.C. supply has been disconnected from relay 40, to discharge through relay 40 and to maintain energization of relay 40 for a predetermined time interval. Relay 42 is connected between the D.C. supply and ground 96 through contact pairs 38-2, 40-3, and 94-1 and is arranged to be energized when all of contact pairs 38-2, 40-3, and 944 are closed. The volt D.C. supply is also connected through contact pair 40-1, shunted by contact pair 943, and contact pair 424 directly to terminal 104 and through diode 106, in addition, to terminal 108. The 60 amp supply of subcircuit 88 is provided from terminal 86 through 2.5 ohm resistor 110, shunted by contact pair 94-2, and contact pair 402 directly to terminal 112 and through contact pair 38-3 and relay 94, in addition. to terminal 114. Relay 94 is arranged to be energized when the voltage across relay 94 is approximately 120 volts. Contact pairs 38-1 and 42-1 are connected in parallel between terminals 116 and 118. Terminals 104, 108, 112, 114, 116, and 118 are mounted on a terminal block 120.

Emergency supply 34 is also arranged to energize the stator (not shown) of the motor in motor-generator set 16. Contact pairs 42-2 are interposed between emergency supply 34 and each of the three phase leads 121 of the stator and are arranged to prevent emergency supply 34 from energizing the rotor until relay 42 is energized and closes contact pairs 42-2.

For installation the subcircuits 84 and 88 are assembled and connected to transformer-rectifier set 82 and terminal block 120 as shown in FIG. 3 and the entire assembly is inserted into a cabinet which is placed adjacent controller 33. Terminal 114 is connected to terminal 78 with wire 122 and terminal 112 is connected to terminal 76 with wire 124. Terminal 108 is connected to terminal 66 with wire 126 and terminal 104 is connected to terminal 68 with wire 128. Terminal 116 is connected to terminal 72 with wire 130 and terminal 118 is connected to terminal 74 with wire 132. Transformer-rectifier set 82 is connected to emergency supply 34 with wires 134, 136, and 138 and contact pairs 42-2 are connected between emergency supply 34 and the stator on the motor in motor-generator set 16.

When normal supply 10 fails, switch 14 opens and contact pair 98 closes. The emergency supply 34 either starts automatically or is started manually, depending upon the facilities available at the particular installation. An authorized employee inserts a key in switch 100, and closes switch 100, energizing relay 38 in control subcircuit 84. Contact pair 38-1 in safety subcircuit 87 opens, thus de-energizing potential switch 64 and disconnecting controller 33 from door motor 28 and brake coil 30. At the same time contact pairs 38-2 and 38-3 close. When contact pair 38-2 in control subcircuit 84 closes, relay 40 becomes energized and opens contact pair 40-3, closes contact pair 40-1 in field power subcircuit 85 (thus energizing the exciter shunt field 61 from terminal 86 through contact pairs 40-1 and 42-4 and terminals 104 and 68 to ground 52) and closes contact pair 40-2 in armature power subcircuit 88 (thus energizing exciter armature 20 which comprises windings 54 and resistor 56 from terminal 86 through resistor 110, contact pair 40-2 and terminals 112 and 78 to ground 52). Armature 20 begins to rotate, thereby rotating motor rotor and generator armature in motor-generator set 16 at the same speed. Diode 106 and resistor 110 initially cooperate to prevent the full voltage applied to the exciter field from being applied to armature 20. Resistor 110 also limits the current in armature 20.

As the speed of rotation of armature 20 increases, the voltage across armature 20, which is shunt-wound, increases. When the voltage across armature 20 reaches approximately l20 volts, relay 94 in armature power subcircuit 88 becomes energized. Contact pair 94-2 is closed, bypassing resistor 110, and the voltage across armature 20, as well as its speed of rotation increases. Contact pair 94-3 in field power subcircuit 85 is closed. in control circuit 84, contact pair 94-1 is closed and contact pair 94-4 is opened.

Capacitor 102 in control subcircuit 84 discharges through relay 40 and prevents relay 40 from becoming tie-energized until the speed of rotation of the motor rotor and the generator armature of motor-generator set 16 is approximately 102 percent of normal idle speed. When motor-generator set 16 reaches that speed of rotation, relay 40 becomes de-energized and opens contact pairs 40-1 (in parallel with now closed contact pair 94-3 in field power subcircuit 85) and 40-2 (in armature power subcircuit 88 thus disconnecting the armature 20 of exciter 18 from the emergency power supply) and closes contact pair 403 (in control subcircuit 84 thereby energizing relay 42).

Energizing relay 42 closes contact pair 42-1 (in safety subcircuit 87 energizing potential switch 64 and thus closing contact pair 64-1), closes contact pairs 42-2 (energizing the motor stator of motor-generator set 16), and opens contact pairs 42-4 (in field power subcircuit 85 disconnecting the shunt field 61 of exciter 18 from the emergency power pp y)- The motor stator of motor-generator set 16 now drives both the generator annature of the set (energizing the armature 22 of main elevator motor 24) and the armature 20 of exciter 18. The voltage across armature 20 is sufficient to switch diode 106 on and maintain exciter shunt field 61 energized and exciter 18, through bus 50 and exciter series field resistance 58, energizes the field 26 of main motor 24. As contact 64-1 is now closed, the exciter also energizes other circuits 66 and the elevator may be operated.

When normal supply resumes operation, contact pair 98 opens and relays 38 and 42 in control subcircuit 84 become de-energized. Contact pair 424 opens, disconnecting the emergency supply from the motor-generator set. In safety subcircuit 87 contact pair 42-1 opens and contact pair 38-1 closes maintaining operation of potential relay 64. Switch 14 closes and the elevator operates on normal supply 10.

As is well known to those in the art, a squirrel cage induction motor, when its rotor is stationary, resembles a transformer having an extremely low impedance in its secondary windings. Consequently, the current, and therefore the power, required to start such a motor is three to five times that required to operate the motor at full load. Typically a 150 to 250 ampere supply is required for this purpose. The use of the circuitry of the invention to drive the exciter electrically to rotate the motor rotor and generator armature until the speed of rotation is approximately the normal operating speed and then switching the emergency supply to drive the motorgenerator set permits the use of low-current (6O ampere) emergency supply to drive the elevator, preferably at a lower speed (approximately 100 feet per minute) than the normal speed. The speed may be reduced by placing normally closed contact pairs on relay 38 in series with several of the elevator acceleration switches. When relay 38 becomes energized for emergency operation, those contacts open and disconnect those acceleration switches with which they are in series from the control circuitry.

Other embodiments will occur to those skilled in the art and are within the following claims.

What is claimed is:

l. The method of utilizing an auxiliary power supply to start the motor-generator set of an elevator system wherein said set has a primary motor having a large starting current requirement which may not be met by said auxiliary supply and wherein the rotor of said primary motor is mechanically coupled to the rotor of a direct current secondary motor having an armature and a field and whose starting current requirement is satisfied by the output of said auxiliary supply. which comprises the steps of energizing said secondary motor from said auxiliary supply by applying power to said field through a first circuit, applying power to said armature through a second circuit, preventing flow of power from said field to said armature until the rotational speed of the coupled rotors reaches a predetermined value at which the current demand of said primary motor is within the output capability of said auxiliary supply;

removing the power applied to said armature when the speed of rotation of said armature reaches said predetermined speed;

and then electrically connecting said auxiliary supply to drive said primary motor.

2. Equipment for utilizing an auxiliary power supply to start an elevator system motor-generator set having a primary motor of large starting current requirement which may not be met by the auxiliary supply, comprising a secondary motor of starting current requirement satisfied by the output of said auxiliary supply and having its rotor mechanically coupled to the rotor of said primary motor, power circuitry for connecting said secondary motor to said auxiliary power supply for accelerating said rotors to a predetermined rotational speed at which the current demand of said primary motor is within the output capability of said auxiliary supply, and

control circuitry responsive to said rotational speed for connecting said auxiliary supply to drive said primary motor after said rotational speed has reached the predetermined value,

said power circuitry including a first subcircuit adapted for electrical connection to the armature of said secondary motor for applying power to said armature and a second subcircuit adapted for electrical connection to the field of said secondary motor for applying power to said field, each of said subcircuits including switching responsive to said control circuitry for effecting electrical connection of said each subcircuit to said auxiliary power supply.

3. The system of claim 2 wherein said armature and field are connected in parallel and said second subcircuit includes circuitry for preventing application of power from said second subcircuit to said armature.

4. The system of claim 3 wherein said second subcircuit circuitry for preventing application of power is responsive to the voltage across said armature for permitting flow of power from said armature to said field when said voltage reaches a predetennined voltage.

5. The system of claim 2 wherein said first subcircuit includes circuitry responsive to the speed of rotation of said armature for limiting the power applied to said armature when the speed of rotation thereof is less than a predetermined speed.

6. The system of claim 5 wherein said circuitry includes a limiting resistor connected in series with and a relay connected in parallel with said armature.

7. The system of claim 6 wherein said control circuitry is responsive to said relay of said first subcircuit for applying power to said primary motor a predetermined length of time subsequent to activation of said relay.

8. The system of claim 6 including switching responsive to said control circuitry for connecting said auxiliary power supply to said primary motor and wherein said control circuitry substantially simultaneously connects said auxiliary power supply to said primary motor and disconnects said first and second subcircuits from said auxiliary power supply.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO. 3,658,156 Dated p il 25, 1972 Inventor(s) Paul Douglas Abbott It is certified that error appears in the above-identified patent and that said. Letters Patent are hereby corrected as shown below:

Column 2, line 13, after "subcircuit insert --59-.

line 16, delete "66 and insert -67-.

Column 3, line +2, delete "11,2" and insert --ll Figure 2, delete "66" referring to "other circuits" (as in Column 2, line 16) and substitute therefor --67--.

Signed and sealed this 8th day of August 1972,

( as Al.

lattes i132 Elli-MR1) ELFLETCHEH TR. RUBSRT GOTTSCHAIWK A ttes ting Gfiicer Commissioner of. Patents FORM PO-1050 (10-69) USCQMMyDC 60376 P69 fi uvs. GOVERNMENT PRINTING OFFICE: 969 0-366-334 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 5 5 Dated April 25, 1972 Inventofls) Paul Douglas Abbott It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 13, after "subcircuit insert --59--.

line 16, delete "66 and insert --67--.

Column Q, line #2, delete "112 and insert ll L--,

Figure 2, delete "66" referring to "other circuits" (as in Column 2, line 16) and substitute therefor --67--.

Signed and sealed this 8th day of August 1972,

A ttes 111-2 EDWARD I-'I.FLJ;TCHER JR. R'QtifiR-T GOTTSCHALK A t has ting Ufiicer v Commi ssioner of Patents FORM PO-IDSO (10-691 USCQMAMDC scan-"p69 u 5. GOVERNMENT PRINTING OFFICE: was o3ss334 

1. The method of utilizing an auxiliary power supply to start the motor-generator set of an elevator system wherein said set has a primary motor having a large starting current requirement which may not be met by said auxiliary supply and wherein the rotor of said primary motor is mechanically coupled to the rotor of a direct current secondary motor having an armature and a field and whose starting current requirement is satisfied by the output of said auxiliary supply, which comprises the steps of energizing said secondary motor from said auxiliary supply by applying power to said field through a first circuit, applying power to said armature through a second circuit, preventing flow of power from said field to said armature until the rotational speed of the coupled rotors reaches a predetermined value at which the current demand of said primary motor is within the output capability of said auxiliary supply; removing the power applied to said armature when the speed of rotation of said armature reaches said predetermined speed; and then electrically connecting said auxiliary supply to drive said primary motor.
 2. Equipment for utilizing an auxiliary power supply to start an elevator system motor-generator set having a primary motor of large starting current requirement which may not be met by the auxiliary supply, comprising a secondary motor of starting current requirement satisfied by the output of said auxiliary supply and having its rotor mechanically coupled to the rotor of said primary motor, power circuitry for connecting said secondary motor to said auxiliary power supply for accelerating said rotors to a predetermined rotational speed at which the current demand of said primary motor is within the output capability of said auxiliary supply, and control circuitry responsive to said rotational speed for connecting said auxiliary supply to drive said primary motor after said rotational speed has reached the predetermined value, said power circuitry including a first subcircuit adapted for electrical connection to the armature of said secondary motor for applying power to said armature and a second subcircuit adapted for electrical connection to the field of said secondary motor for applying power to said field, each of said subcircuits including switching responsive to said control circuitry for effecting electrical connection of said each subcircuit to said auxiliary power supply.
 3. The system of claim 2 wherein said armature and field are connected in parallel and said second subcircuit includes circuitry for preventing application of power from said second subcircuit to said armature.
 4. The system of claim 3 wherein said second subcircuit circuitry for preventing application of power is responsive to the voltage across said armature for permitting flow of power from said armature to said field when said voltage reaches a predetermined voltage.
 5. The system of claim 2 wherein said first subcircuit includes circuitry responsive to the speed of rotation of said armature for limiting the power applied to said armature when the speed of rotation thereof is less than a predetermined speed.
 6. The system of claim 5 wherein said circuitry includes a limiting resistor connected in series with and a relay connected in parallel with said armature.
 7. The system of claim 6 wherein said control circuitry is responsive to said relay of said first subcircuit for applying power to said primary motor a predetermined length of time subsequent to activation of said relay.
 8. The system of claim 6 including switching responsive to said control circuitry for connecting said auxiliary power Supply to said primary motor and wherein said control circuitry substantially simultaneously connects said auxiliary power supply to said primary motor and disconnects said first and second subcircuits from said auxiliary power supply. 